Legal Medicine 9 (2007) 88–93
www.elsevier.com/locate/legalmed

Restraint asphyxia in in-custody deaths
Medical examiner’s role in prevention of deaths
Lakshmanan Sathyavagiswaran
a

a,*

, Christopher Rogers a, Thomas T. Noguchi

b

Office of Chief Medical Examiner-Coroner, County of Los Angeles, Department of Coroner, 1104 N. Mission Road, Los Angeles, CA 90033, USA
b
University of Southern California, Keck School of Medicine, Los Angeles, CA, USA

Abstract
In the United States, the office of the Medical Examiner-Coroner is responsible for investigating all sudden and unexpected deaths
and deaths by violence. Its jurisdiction includes deaths during the arrest procedures and deaths in police custody. Police officers are sometimes required to subdue and restrain an individual who is violent, often irrational and resisting arrest. This procedure may cause harm to
the subject and to the arresting officers. This article deals with our experiences in Los Angeles and reviews the policies and procedures for
investigating and determining the cause and manner of death in such cases. We have taken a ‘‘quality improvement approach’’ to the
study of these deaths due to restraint asphyxia and related officer involved deaths, Since 1999, through interagency coordination with
law enforcement agencies similar to the hospital healthcare quality improvement meeting program, detailed information related to
the sequence of events in these cases and ideas for improvements to prevent such deaths are discussed.
Ó 2006 Elsevier Ireland Ltd. All rights reserved.
Keywords: Restraint asphyxia; Positional asphyxia; Custody death; Hogtying restraints; Forensic medicine; Medical examiner-coroner

1. Introduction
In California, by State law, the Department of Medical
Examiner-Coroner is an independent investigative agency
responsible for the official investigation of all sudden and
unexpected deaths, deaths by violence or deaths under suspicious circumstances. Many states have laws extending
jurisdiction to investigate deaths due to infectious diseases
that constitute a public health hazard, deaths during therapeutic and diagnostic procedures, and case review before
cremation. The medical examiner also has jurisdiction to
investigate deaths during custody of law enforcement and
justice agencies. Although the medical examiner in the
United States is an independent agency, we work with
law enforcement agencies in the investigating of homicide
cases, including officer involved deaths and deaths while
under custody.

*

Corresponding author. Tel.: +1 323 343 0522; fax: +1 323 225 2235.
E-mail address: lsathyav@coroner.co.la.ca.us (L. Sathyavagiswaran).

In 1988, Reay et al. [1] first reported on an experimental
study on the detrimental physiological effects associated
with the ‘‘four point restraint’’ procedure, commonly
known as hogtying or hobble restraint. In a subsequent
paper in 1992, Reay et al. [2] reported on three cases of
deaths from positional asphyxia after the victims had been
placed in a prone position in the rear compartment of a
police patrol car. O’Halloran et al. in 1993 [3] reported
on eleven cases of sudden death of men restrained in a
prone position by police officers. Nine of the men had been
hogtied, one had been tied to a hospital gurney, and one
was manually held prone. All subjects were in an excited
delirious state when restrained. Three were psychotic, and
the others were acutely delirious from drugs (six from
cocaine, one from methamphetamine, and one from
LSD). In a second paper [4] O’Halloran reported on two
additional cases of deaths of psychotic patients under
restraint.
In the Los Angeles cases reported in 1995 by Stratton
et al. [5] two unexpected deaths occurred in restrained
(hogtied) agitated individuals while they were being

1344-6223/$ - see front matter Ó 2006 Elsevier Ireland Ltd. All rights reserved.
doi:10.1016/j.legalmed.2006.11.007

L. Sathyavagiswaran et al. / Legal Medicine 9 (2007) 88–93

transported by advanced life support ambulances. Law
enforcement personnel had placed both patients in hobble
restraints. Toxicological analysis revealed non-lethal levels
of amphetamines in one patient and non-lethal levels of
ethanol, cocaine, and amphetamines in the other. Stratton
et al. in 2001 [6] reported on 18 other cases of such deaths
witnessed by emergency medical service (EMS) personnel.
In all 18 cases, the individuals had been restrained with
the wrists and ankles bound and tied together behind the
back. Associated with all these sudden death cases was
struggle by the victims against the forced restraint, followed by cessation of struggling with labored or agonal
breathing immediately before cardiopulmonary arrest.
Also associated were stimulant drug use, chronic disease,
and obesity. The report noted that unexpected sudden
death when excited delirium victims are restrained in the
out-of-hospital setting is not infrequent and can be associated with multiple predictable, but usually uncontrollable,
factors.

89

rendering a cause and manner of death, and to communicate with the police department to elucidate the cause
and mechanism of death, and provide the key information
for prevention of similar deaths in the future.
2.2. The standard autopsy procedures

2.1. Investigative aspect

A well-qualified forensic pathologist is assigned to conduct such autopsies. The external examination should be
meticulous. The pathologist should note and record even
faint subtle bruises and abrasions. They may later become
important, correlating circumstantial investigative findings
with injuries, particularly the time of injuries. The direction
of force of abrasion may become a crucial issue. Equal
importance should be placed on any absence of injury on
the head, neck, upper extremities as well as the lower
extremities and the genitals. If there is any evidence of
physical contact to the decedent, it is presumed that the
contact may be the lethal act and all caution should be taken to properly document it. For the examination of the
neck, it is important to look for petechial hemorrhages in
the conjunctivae and the buccal mucosa in conjunction
with hemorrhages in the neck. It should be noted that
any injury or existing natural disease could act in concert
with or be contributory to the cause of death. Complete
and thorough detailed documentation of all findings is
essential as the basis of assigning the proximate cause of
death. Special procedures to be followed for reducing the
chance of missing important findings include:

In-custody deaths include deaths that occur during
apprehension by police officers, and deaths while the subject is detained or incarcerated in a public institution.
When death occurs under these circumstances, it is the duty
of the Medical Examiner-Coroner staff to respond to the
scene, take charge of the body, and investigate the circumstances surrounding the death. These situations often trigger accusations and emotional outbursts by the family
members and community activists, and can also lead to litigation. Investigations into the cause and manner of these
deaths, therefore, require sensitive, timely and thorough
processing, since it is expected that scrutiny by investigative
agencies, the media, and the pubic as well as the families
will follow. In Los Angeles County, the team approach is
used in handling these cases. Such deaths raise the question
of the use of excessive force, procedures which are illegal,
or have high risk of causing injury or even death, so the
inquiry extends into the possibility of illegal acts of commission or omission of the police department in restraining
the arrestee, resulting in death.
The police department is often concerned about undue
lawsuits against the department and criminal prosecution
of the involved police officer. The Medical Examiner’s role
in these cases is to handle them with sound, thorough
investigation by a systematic process of observing, recording, gathering and preserving evidence and information
and by subsequent analyses of the data with the goal of

(i) Multiple photographs should be taken to document
each injury with a ruler.
(ii) To compare the pattern, photographs should be
taken at vertical angle.
(iii) Photographs should include whole body/all aspects.
(iv) Photographs may need to be enlarged to see the
details, so use fine grain negative film with adequate
lighting, so that magnification can be done without
loss of resolution.
(v) The medical examiner should collect samples of hair,
fingernail clippings, oral/genital swabs and preserve
clothing and other articles that may be related to
the death. These items should be placed in properly
aerated containers to prevent decomposition of the
biological evidence.
(vi) X-ray of the neck should be taken, even if externally
negative. For further detailed study, postmortem
vertebral artery perfusion is recommended.
(vii) Save adequate specimens and conduct toxicology
studies including carboxyhemoglobin, volatiles, and
drugs of abuse as indicated
(viii) Where indicated, microscopic studies on heart, lung,
liver, and kidneys should be conducted to assess
existing disease.
(ix) Specific attention should be directed to injury areas to
estimate time of injury. Meticulous documentation
and correlation of the injury should be included.

2. Death investigation – policy and procedure
In Los Angeles, the following standards, policy and procedure were established for investigation of such deaths: 1.
Investigative aspect, 2. Autopsy and specimen analyses, 3.
Management of cases, 4. Cause and effect analyses with
the aim of prevention.

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(x) For assessment of finer neuropathologic changes, the
brain and spinal cord should be fixed and examined
by a neuropathology consultant as warranted.
In cases of death in prison or jail, in order to understand
the incident better, it may be necessary to obtain information from the victims custodian and other inmates. Prison
riots and gang activity may also result in deaths in prison
custody and are important factors in coming to a
conclusion.
2.3. Management of the case
For overall management of the investigation with focus
on the search for reliable information and rendering a
reasonable conclusion, a number of points need to be
understood. There may be pitfalls in in-custody death
investigation. The final conclusion may have a great impact
on the community and agency policy making, so it is
important to use caution in recognizing injury as the primary or contributory cause of death. If injury contributes
to death, the death is assignable to the injury event, regardless of the nature and extent of an existing primary natural
disease. Careful assessment to evaluate whether events are
coincidental or related must be on ‘‘the scale’’ used to
assess the death. Premature and inappropriate release of
information to a suspicious public may result in suspicion
of unwarranted and inappropriate conduct by authorities.
At the same time, it is more harmful not to release information that may often be interpreted as concealment of
misconduct. Before release of information, all work and
evaluation should be completed, but it must be in a timely
fashion. Conclusions must be circumspect.
In Los Angeles County, when the manner of death is
classified as homicide, this only means that a person died
as a result of a direct action of another person. It means
the death was at the hands of another. Further note that
the term murder is a legal classification that should only
be used by charging authorities, i.e., the district attorney.
2.4. Cause and effect analysis and special consideration
Assignment: The in-custody death investigative team is
assigned to investigate such cases at scene. The Chief Medical Examiner-Coroner and the Chief of Forensic Medicine
Division will conduct the final reviews. In order to review
those cases, it is necessary to be able to reconstruct the
scene.
Necessary documentation: At-scene investigation of the
undisturbed body is necessary. If paramedics have removed
the body for emergency care, it is necessary for the medical
examiner to review all photographs and descriptions of the
scene taken and provided by the investigating agencies. All
available preliminary information is taken into consideration before the autopsy is performed, but all information
must eventually be confirmed. The records of the police
agency are reviewed, including all statements of persons

who witnessed the event and persons who were in proximity to the scene of death.
Information on restraints in detail: If physical restraint
was used, a detailed description of the method of restraint
is necessary. The description should include: (a) what type
of restraint, (b) what period of time, (c) position of victim
when the restraint was applied and during the restraint
period, the final resting position, (d) any use of arms,
shackles, handcuffs, flexcuffs, choke hold, the use of taser,
pepper spray or any additional restraints, such as hogtying.
Approach in investigation of in-custody deaths: The Los
Angeles Office looks at the types of restraint measures
used, which can include the use of pepper spray, taser,
swarm techniques, baton use, handcuffing, ankle restraint,
four point restraint or hog-tying, etc. Investigation looks
into whether or not these restraining procedures were
applied separately, intermittently, or together. It is important for us to also know how many officers were involved in
apprehending or subduing a suspect who required restraint
or use of force. We then look at how long and what types
of restraint measures were applied. We gather independent
observations regarding the consciousness, mobility, and
actions of the suspect during this process. When a victim
had been taken to a hospital, we evaluate the paramedic
report, the medical treatment and the hospital toxicology
reports, and include obtaining the hospital blood for further toxicological analyses. The autopsy is most comprehensive for these types of cases and includes fluoroscopy
and X-rays as needed. Neuropathology studies and microscopic studies are generally performed/supervised by one of
our full time, Board Certified staff pathologists. During
autopsy, we also look for injuries, preexisting medical
conditions, and drug intoxication.
3. Medical examiner’s role in prevention of death
The critical aspect in each case is the chronology of
events. We rely heavily on independent observations, as
well as the internal review process by the law enforcement
agency. Paramedics should be reminded to take body
temperature as part of their evaluation. In the past we have
experienced difficulties in acquiring information due to the
fact that officers involved in the apprehensions often exercised their Fifth Amendment rights against self-incrimination guaranteed by the U.S. Constitution. Typically, we
experienced the following types of cases: During a ‘‘swarming’’ technique, several officers try to handcuff an unusually
heavyset large suspect and apply ankle restraints. Oftentimes a baton is used to bring down the suspect and usually
the suspect ends in a face down position often with officers
kneeling on or sitting on the arrestee. Even though the
actual ‘‘hog-tying’’ procedure may or may not have been
a factor, multiple officers sitting on the back of an obese
person can restrict his/her respiration. Hence the term, ‘‘restraint asphyxia,’’ is used to described the cause of death in
these cases. The role of the Medical Examiner is not only to
determine the cause and manner of deaths, but also to take

L. Sathyavagiswaran et al. / Legal Medicine 9 (2007) 88–93

action in informing the appropriate agencies to reduce
unnecessary deaths and suggest appropriate actions for
correction.
In Los Angeles County, the Chief Medical ExaminerCoroner (CME-C), noting these cases of deaths during or
following police arrest procedures, communicated with an
official letter to the Office of the City Attorney (Sathyavagiswaran, personal communication), informing them of the
Coroner’s Office procedures and findings, suggesting that
the district attorney’s office and/or the city attorney’s office
should institute an independent investigation or field a
response team to check into the police arrest procedures
resulting in these deaths. Further suggestion was made that
in these situations paramedics should also be summoned at
the same time as the police, so medical assessment of the
individual disturbing the peace can be made immediately.
These individuals are often under the influence of drugs
and/or have preexisting medical conditions.
It was strongly suggested that these incidents be videotaped in entirety whenever possible. Videotaping is very
useful for studying the activities of the victim before apprehension and the effect of the restraint maneuvers used.
When restraint is used, it advised that apprehended suspects be placed in the lateral decubitus or sitting position
and to avoid placing them in a face down position, placing
weight on their back, and hogtying them. At the first sign
of physical difficulty, take him/her to a hospital where specialists are available to evaluate and clear the person before
he/she is taken to a jail facility.
Finally, the Medical Examiner suggested a multi-disciplinary team conference to evaluate the sequence of events,
so there is consistency in information provided. A strong
message was sent to the City Attorney’s Office by the
CME-C that hog-tying compromises lung volume and
respiratory function and recommended the use of alternative restraint maneuver. In response to a grand jury recommendation, since October 1999 in Los Angeles County a
multi-disciplinary team composed of representatives from
the police departments, the sheriff’s office, the district attorney’s office and the Medical Examiner have met regularly
in a forum to freely exchange information and ideas to
address areas of mutual concern and improve the arrest
procedure to reduce injury and prevent deaths.
4. Manner of death
Concerning classification for the manner of death, Los
Angeles County Coroner’s Office established the following
standards for determining whether or not deaths following
a hog tying incident should be determined as homicide or
undetermined. In a joint meeting with the DA and police
chiefs, the CME-C indicated that if the following combination of multiple factors is involved, the manner of death is
classified as undetermined. The factors are (1) obesity and
enlargement of the heart, (2) laboratory tests show drugs in
the system, (3) psychiatric history and psychotic reaction,
(4) high risk (unsafe) arrest procedure, (5) insufficient

91

information to explain the sequence of events, (6) either
insufficient information or conflicting information which
affects the Medical Examiner’s ability to make a final determination. The Medical Examiner may determine the manner of death as undetermined as a signal to law
enforcement that the case warrants more in-depth investigation to try to answer some of the questions surrounding
the death. Undetermined is also used by the Department of
Coroner when the autopsy findings do not establish any
specific cause of death, such as the case of a young person
without heart disease or other existing diseases, no drug in
the system, yet dying following the restraint procedure.
When the manner of death is determined to be homicide,
it simply means the death was at the hands of another.

5. Discussion
5.1. Mechanism of death
There has been much discussion as to whether or not
the prone position per se would cause death of a hog-tied
individual. Reay et al. in 1988 [1] reported on the effects
of positional restraint on oxygen saturation and heart
rate, and noted that positional ‘‘hog-tie’’ restraint induced
prolonged recovery time. He concluded that persons
placed prone, handcuffed, and ‘‘hog-tied’’ expire as a
result of the physiological effects produced by positional
restraints and reported deaths of hog tied individuals were
due to ‘‘positional asphyxia.’’ Other reported cases of
deaths of hog-tied individuals [2] all indicated that the
hog-tied persons had been placed prone (face down) on
a surface.
A Los Angeles County Coroner study (Rogers C, Russell MA, Eckstein M, Mallon W, Aguilar G, unpublished
observations) monitored the heart rate and blood oxygen
saturation of 10 subjects in four-point restraint in the hyper
extended position, and compared this with restraint using
two commercially manufactured restraint devices. Positional differences were studied. The subjects were placed
in the prone and left lateral decubitus positions. Recovery
of heart rate after exercise was significantly better with the
limbs partly extended on the left side (left lateral decubitus
position). Most subjects did not experience significant oxygen desaturation during restraint, although desaturation
did occur in some subjects. The authors emphasized that
four-point restraint in the hyper extended position is associated with potentially dangerous physiologic changes. The
use of restraining devices that do not hyperextend the limbs
was recommended.
Chan et al. [7] determined whether the ‘‘hobble’’ or
‘‘hogtie’’ restraint position results in clinically relevant
respiratory dysfunction and concluded that, in a population of healthy subjects, the restraint position resulted in
a restrictive pulmonary function pattern but did not result
in clinically relevant changes in oxygenation or ventilation,
although a small restrictive pulmonary function pattern by

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pulmonary function test parameters was found in subjects
who were placed in the restraint position.
Parkes [8] measured the effects of restraint positions on
recovery rate from exercise in healthy individuals and concluded that physiological effects produced by positional
restraints should be recognized in these deaths.
In a more recent study Chan et al. [9] reported that the
prone maximum restraint position with and without 25 and
50 pounds of weight force resulted in a restrictive pulmonary function pattern, but no evidence of hypoxia or
hypoventilation was noted.
In experimental studies, it is difficult to simulate the real
police arrest situation and experimental studies done on
healthy individual surely cannot reproduce the real situation. There is no disputing the fact that there have been a
number of deaths reported of unusually agitated individuals enduring restraint by hogtying procedure in police custody. There are certain characteristics that distinguished
these individuals, who died while hogtied in police custody.
It goes without saying that hogtying is used by the police in
controlling unmanageable irrational and violent individuals who may cause harm to themselves as well as to others.
Stratton et al. [6] delineated the factors associated with
the sudden deaths of agitated individuals who are placed
under restraint for excited delirium. These are the individuals who are often subjected to hogtying when a family
member calls the police to help control the person.
1. ‘‘Associated with all sudden death cases was struggle by
the victim with forced restraint and cessation of struggling with labored or agonal breathing immediately
before cardiopulmonary arrest.
2. The findings were also associated with stimulant drug
use (78%), chronic disease (58%), and obesity (56%).
3. The primary cardiac arrest rhythm of ventricular tachycardia was found in 1 of 13 victims with confirmed initial
cardiac rhythms, with none found in ventricular
fibrillation.
4. Authors indicate that unexpected sudden death when
excited delirium victims are restrained in the out-of-hospital setting is not infrequent and can be associated with
multiple predictable but usually uncontrollable factors.’’

live volunteers as subjects. The re-enactment is videotaped.
Deaths associated with restraint often have non-specific
autopsy findings. Timely reenactment of the circumstances
of deaths associated with restraint can help death investigators to more accurately determine the probable cause of
deaths in such difficult cases. Such cooperative studies on
the step by step effect of the restraint process which led
to the death can be educational and help to elucidate what
should be avoided to prevent such deaths, similar to the
quality improvement program for patient care in the hospitals. In Los Angeles County, videotaping is used during
actual arrest procedures. In case of death, the video is made
available for evaluation of the mechanism of death. The
CME-C and chiefs of police are in regular contact, sharing
pertinent information to effectively prevent repeated deaths
by similar means.
5.3. Quality improvement approach to prevention of death
Because of the litigious atmosphere here, the police
agency is often reluctant to provide the medical examiner
with pertinent information related to the sequence of
events leading to the death of a person under its custody.
We propose that a new team approach be set up to prevention of similar deaths. Earlier, for decades a similar blaming atmosphere confronted the healthcare providers and
facilities and doctors and hospitals faced repeated malpractice litigation that prevented more earnest exchange of
information and setting up a program for improvement.
Beginning in the mid-1970’s in California, concerned physicians formed a multi-disciplinary team to evaluate the
causes of preventable deaths, and made a concerted multi-pronged effort in improvement in the quality of patient
care by implementation of quality assurance and setting
up improvement forums for earnest exchange of fact finding and open discussion of problems without fear of information being used to harm doctors’ and/or hospitals’
reputation. This concept was found to provide the most
effective way to prevent repeated similar complications
and deaths. Any documentation under this provision will
not be the subject of discovery for legal action.
5.4. Manner of death

Deaths of hogtied individuals are not attributable simply
to hogtying. Multiple factors are involved. These individuals
are already compromised by drug use and/or mental aberrations triggering other physical disabilities. Their uncontrollable actions force family members to call the police for
help and the responding police use their training and procedures to subdue and control these individuals.
5.2. Innovative investigation technique
O’Halloran [4] presented an innovative approach by reenactment of the restraint procedure using the actual
restrainer. Within a day of the autopsy the restrainer participates in reenactments of the restraint process, utilizing

So far, we do not have any national consensus on the
manner of death in these specific types of police-involved
deaths. Reay [10] recommended accidental classification.
Hirsch in New York City [11] recommended homicidal
classification when the restraint position constitutes use
of a ‘‘potentially lethal force.’’ However, most of the
reported cases have involved young men in a state of ‘‘excited’’ or agitated delirium as a result of intoxication from
recreational drugs or psychiatric illness. In addition, these
individuals had often suffered traumatic injuries before
placement in the restraint position. In Los Angeles we
would use the undetermined classification for those
restraint deaths with multiple contributing factors. In

L. Sathyavagiswaran et al. / Legal Medicine 9 (2007) 88–93

California, O’Halloran [12] recommended certifying these
cases as accident or, if a disease was the main factor, then
certifying as natural. Many medical examiners determine
the manner of such deaths to be accident, meaning that
the event happened by chance, or unexpectedly; taking
place not according to usual course of events. An accident
results from an act that is lawful and lawfully done under a
reasonable belief that no harm is possible.
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restraint on oxygen saturation and heart rate following exercise. Am J
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[2] Reay DT, Fligner CL, Stilwell AD, Arnold J. Positional asphyxia
during law enforcement transport. Am J Forensic Med Pathol
1992;13(2):90–7.
[3] O’Halloran RL, Lewman LV. Restraint asphyxiation in excited
delirium. Am J Forensic Med Pathol 1993;14(4):289–95.

93

[4] O’Halloran RL. Reenactment of circumstances in deaths related to
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[5] Stratton SJ, Rogers C, Green K. Sudden death in individuals in
hobble restraints during paramedic transport. Ann Emerg Med
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